Research On Welding Deformation Control Process Of Thin Wall Structure In Combustion Chamber

The main combustion chamber of an aero-engine is one of the important components of the engine.The material is generally made of high-temperature alloy,and the overall structure is usually a thin-walled cylinder structure.This structure is prone to unstable deformation when performing straight seam butt welding.This paper will use finite element simulation technology to analyze the results of welding instability and residual stress of thin flat and thin-walled cylinders,as well as the improved method of rigid fixing method-back strengthening method and welding time difference stretching method.The post-weld deformation and residual stress results of the welding deformation control method are predicted.In this subject,a 300×200×1mm GH5188 thin plate was tested for butt joints and welded by pulsed TIG welding.The welding thermal cycle,deformation and residual stress are measured to facilitate subsequent verification of the welding heat source.At the same time,the plate was numerically simulated,and the simulated data was compared with the experimentally measured data.The results of the two data were in good agreement.The heat source parameter is used to predict post-weld deformation and post-weld residual stress.The numerical simulation of the thin plate butt welding under the rigid restraint method is better than the original model.Given the increase of the width of the press plate,the flexural deformation and the angular deformation are first reduced,and then remain unchanged.As the distance between the press plates and the weld increases,the flexural deformation and angular deformation are reduced.Since the rigid restraint method has problems in the actual test,an improved method and a back strengthening method are given.The numerical simulation results of thin plate docking under this method show that the angular deformation and flexural deformation are better than the original model.As the width of the reinforcing cloth increases,the flexural deformation decreases,but the effect is not obvious;the angular deformation is reduced first,and then the maintenance is not maintained.change.As the thickness of the reinforcing cloth increases,both the flexural deformation and the angular deformation decrease.A thin plate docking test was carried out,which has a good effect on controlling the flat plate.It is used for th e deformation and residual stress prediction of the thin-walled cylindrical structure.The final deflection degree of the thin-walled cylindrical structure is 4.82 mm,and the overall circularity difference of the cylinder is 2.47 mm.The numerical simulation of the thin plate welding by the temperature difference stretching method at the welding time shows that as the temperature in the high temperature zone increases,the deflection deformation first decreases,and decreases to a very small value at 200 ?,and the temperature rises and the deformation direction is reversed.With the increase of the distance from the weld in the high temperature zone,the flexural deformation gradually decreases,and after a certain distance,it remains unchanged;the angular deformation first increases and then decreases,and then remains unchanged.The residual stress decreases with the increase of the temperature in the high temperature zone;it decreases first and then increases as the distance from the weld zone increases.The method is applied to a thin-walled cylinder,and the final welding deflection degree of the thin-walled cylindrical structure is 0.307 mm,and the overall circularity difference of the cylinder is 0.695 mm.